Method of producing an adsorbent



Patented Aug. 30, 1949 METHOD F PRODUCING AN ADSORBENT CLEANING MATERIAL William S. W. McCarter, Bala-Cynwyd, Pa., assignor to Attapulgus Clay Company, Philadelphia, Pa., a corporation of Delaware 'No Drawing. Application November 28, 1945,

Serial No. 631,479

4 Claims.

The present invention relates to improved adsorbent cleaning compositions and method of making same, and relates more particularly to low density, highly adsorptive clay-type compositions suitable for use in removing oil, grease, WaterLand the like from surfaces such as woo-den or ,concrete floors, linoleum, paper and fabrics.

I have found that satisfactory cleanin compositions should be characterized by a high oil retention, a low density. or volume weight, and a high resistance to attrition or breakdown upon use. Low bulk density or volum weight is desired because the lower the volume weight, the greater the surface area which can be covered by a given weight of cleaning composition. Hardness or resistance to attrition is necessary, since a soft, readily powdered material is' difficult to remove from the surface being cleaned. High oil retention is desirable in order that a minimum amount of the cleanin composition may be used in removing oil, grease and the like from the surface being cleaned.

It is obvious, however, that a decrease in volume weight of the cleaning composition without any change in other properties does not constitute an improvement. For example, let it be assumed that two adsorbent cleaners have the same oil retention upon a weight basis, but that the first cleaner has one-half the volume weight of the second. The first cleaner will have twice the covering power of the second, assuming that layers I of equal thickness are used. In spite of the greater covering power, the first cleaner is not better than the second because in order to adsorb the same amount of oil per unit'area, the layer of the first cleaner would have .to be twice as thick as that of the second cleaner. In general, a lowering of volume weight is desirable if the oil retention can be increased correspondingly,

and the factor which shows the relative merits of various cleaners is the oil retention on the volume basis I have found that improved adsorbent cleaning compositions may be prepared by incorporating with a plastic adsorbent clay, a suitable quantity of a cellulosic material, intimately admixing the clay and cellulosic material, drying the mixture, reducing the dried material to granules of desired size, and calcinin the granules at elevated temperature.

In accordance with my invention, an adsorbent clay such as fullers earth is mixed with a cellu losic material such as sawdust, wood flour, or

paper pulp, and the water content of the mixture 'is adjusted by the addition of Water, if necessary,

to a value between 40% and by weight, and preferably between 53% and 56% by weight. The ratio of cellulosic material to fullers earth may range from 1 part to 30 parts by weight. For example, in a sawdust-fullers earth mixture, the sawdust may represent from 1% to 30% by weight of the mixture, with preferred amounts ranging from 5% to 25%. In a wood flour-fulleris earth mixture the same proportions may be used, and with apaper pulp-fullers earth mixture, about to;2% of pulp gives satisfactory results. The mixing may be carried out in a pug mill or other conventional mixer, and the plastic mixture is then delivered to an auger extrusion machine provided with a die plate containing a plurality of holes of suitable diameter, for example, A inch to 1 inch in diameter depending upon the size and output of the extrusion machine. The plastic mixture, in passing through the extruder is thoroughly kneaded and compressed, and is discharged through the die plate orifices in the form of cy lindrical pieces of irregular length. The ex? truded material is then dried at temperatures between 200 F. and 300 F. to remove the bulk of the: free moisture, and the dried material is then ground and screened to give granules of desired particle size, for example, 10/60 mesh, 30/ 60 mesh, etc. The granularmaterial is then calcined by heating in a kiln or clay burner at an elevated temperature preferably between 750 F. and 1200 F. until the volatile matter content is reduced to 10% by weight or lower, for example, 1% to 5% by weight. At 750 F. the cellulosic content of the granules is carbonized and partly consumed by oxidation, whereas at 1200 F. the cellulosic content is almost completely removed by oxidation. In either case there is obtained an adsorbent cleaning composition of lower volume weight and higher oil retention than i produced by a similar treatment of fullers earth without the added cellulosio material. While it is preferred to use an extrusion machine in conjunction with a pug mill to obtain uniformity and hardness of product, the mixing of the fullers earth and cellulosic material to form a plastic mixture may be carried out in a pug mill alone; and the mixture may be discharged directly into suitable dryin equipment.- After drying, the mixture is then ground, screened, and calcineda's described hereinbefore.

The adsorbent clay employed in accordance with this invention is preferably fullers earth of the type mined in Georgia and Florida, although earths from other sources may be used. As mined, the raw fullers earth usually has a total volatile 3 matter content (mostly water) of the order of 47% to 49% by weight, and this water content must be taken into account in preparing the fullers earth-cellulosic material mixtures, all

period of time. A graduated glass cylinder of 100 cc. capacity is filled with the granular material and clamped to a reciprocating platform which is raised and lowered through a distance of 1% inch calculation being made upon the basis of dry by means of a cam rotating at 250 R. P. M. The earth. Forexampla-in lm parts of:a:p1astic mixsettllng device "isbperated 'for exactly 5 minutes, ture suitableffor extrusion, the l'fuller s earth may and the cylinderis refilled to the1=100 accsmark by comprise 39 P rts y W ig (dry), t e c ulesic carefully adding more granular material through material '7 parts by weight, and Water 54 parts by a funnel, the cylinder not being moved or jarred weight. The proportions of "fuller-'5 earth and .10 duringthe additiomof the make-up. The cylcellulosic material may vary considerably, but the inder and contentsis weighed to the nearest 0.1 Water content is preferably maintained between gram, then emptied and weighed empty. The dif- 50 and 60 Baits 0 pa tsfi ithatotal 'ference represents the weight of 100 cc. of granuture. The cellulosic material-"ispreferably'sawla material,'which is readily converted to pounds dust obtained by the fine sawing of kiln-dried 7 'percubic foot W of a light Species such as redwood, although 7 :Oil retention on 'a weight basis was obtained other sawdusts have been found satisfactory. In i'bytmi i 50 grams of th granular m t ial ith general, the mesh e of the Sawdust Should not an excess of a standard lubricating oil described exceed the maximum mesh size desired in =t'he b l pouring th mi t on 4 i h B h granulated adsorbent cleaning composition. For funnel and sucking the mntents of t fu l dry e l 'theifinal l ducit is :in "the form o icy-applying reduced'pressure"( IB inches mercuIy) lfl/fidm'eshfgranulesgthesawdust 0I"0thlJCG11ll- 2 hgurs 1 150 11 The granular materlalii Tosic materialshnuldmotbe:coarserzthan 10 mesh. reweighed and thegain inweig'ht is rtainedon The finerttheparticles of cellulosiamaterial, the From the Value f nd grams im a d y aretheymiifmmly'incorFortifiedwith the oil retention inpounds per pound'of-m'aterial Q' t can readily becalculated. To-determine-the'oil 33319311: tms IFspec't, 'alfdlpaper l less Smtableretention'on the volume basisfit isnecessaryonly My "invention may be further ill rby to multiply the volume weight ofthe "granular followmg exampiles'flwhlch" however "areinot material by the value for theoilretentioniomthe q be ?011S m1efiaS hm1tms"thesmpe thereofweight basis. The oil employed had thefollowing Cel1ulos1c;.mater1al was added to raw fullers properties; 'ea'rthin various ratios; the water .c'ontent-of the 7 mixtures then b-eing adjusted to about 154% *by Saybold lviscosit -9.11 100"F. weight. The mixtures were thoroughly .pugged 0 0 Seconds inaconventional pugmilland then charged'to an saybolt umversal 'Vlscoslty at 210 auger extrusion machine provided with a-dieplate Seconds" inch in thickness an'dtcontaining a plurality L gravlty "degrees" 213 'of apertures each %inch in diameter. The mixfl 9 tures were extruded from'the;dieplate apertures pomt at an elevated pressure above 100 pounds per Pour "test square inch inthe form of relatively -hard,-cylin- Color 312 'drical rods of irregular length. "Theextruded ma- Other lubricatin oils of generally=similar propterial was'dried at. 220 Fyto amoisture content erties, particularly viscosity, maybe-used inlieu between 15% and 30% "by weight, andthe dried of the-above without materially-changingthetest material was ground and screened to produce '45 results. granules of 10/60'mesh. Thegranular material The results of the'testson compositions prewasthen calcined at elevatedtemperatureto'give pared-as hereinbfore'described are given 'in'thea 'volatilematter content 'of not more than about 'followingtable.

Percent r figggggg gre 331? Xitfii ttlit idttief "Added Percent lbs/cu. it. lbs. per lb lbs:/cu.ft.

I n None" 750 5.3 34.5 0.716 24.7 Rcdwood sawdust 5 -750 4.2 29.9 p.838" 2551 -Do 15 750 4.8 28.4 0:876 24. 9 25 750 5.2 '28. 0 05882 24.7 Yellow pine so. dust 15 i 750- 10.0 3014 846 25;! o 15 1,000 4. a 31. e o; 836- 26 4 0 25 1,000 '5. 1 '29. 8 0.867 25.8 White, pine. sawdust .4 10 750 s; 3 30:9 0. s00 24;? Do l- 750 4.3 31.0 0.836- =-2s.e Do :25 750 10.0 29:7 0:874 "25.9 :Paper ul 1.1 .750 4.4 30.8 $0300: 2451 2. s 750 r 5 29. 1 o. 876 2525 10% by weight. The volatile matter content-was -From=the;abover data, .it will be seen that im- .cletermined by heating-a weighed sample.at-1800 .05 proved adsorbent cleaning compositions may-be F. for 30 minutes, cooling and reweighing :tonobobtained by incorporatingifinely divided cellulosic tain the percent loss. The calcinedgranular mamaterial with the vfullers earth, extruding the terial was tested for volume weight and for oil mixture, and calciningithe granular :product. In retentionraccording to the followed methods. general,.I-have found'ethatztcompositions, particu- Volume weight was obtained :by settling the 7.0 larly 10/60 mesh compositions having a'wdlume granular material under regulated conditions. weight between =26;and 32 ipOHIIdS DGI CU-biC foot, Reproducible settling conditions are :achieved an oilretention between10:8zandI0192poundsmer through the use-of a .device which repeatedly lifts pound of earth, and between 2l andi27pounds per and drops a container of the =material a fixed cubic footof earth,iand.-a volatile matter-"content distance, .at'a definite rate,and for "a measured #5 'of not-more than 10%;are markedly superior-to ordinary fullers earth as cleanesr for oil, grease, and the like. My improvement resides in decreasing the volume weight, thereby increasing the covering power, without adversely affecting the oil retention on the volume basis. In employing a cellulosic material in amounts ranging from 1% to 30%, and preferably from 5% to 25%, I am able to produce highly efiicient cleaning compositions having a satisfactory hardness and resistance to disintegration, whereas with more than about 30% of cellulosic material, the product usually is characterized by an undesirable softness.

I claim:

1. A method of producing an adsorbent cleaning material, comprising forming a mixture of from 1 to 30 parts by weight of cellulosic material selected from the group consisting of sawdust, wood flour, and paper pulp, and from 99 to 70 parts by weight of fullers earth, adjusting the water content of the mixture to a value between 40% and 60% by weight, extruding the mixture at elevated pressure above 100 pounds per square inch, drying the extruded mixture, reducing the dried mixture to granular particles, and calcining the particles at a temperature between 750 F. and 1200 F. for a period of time sufficient to obtain a volatile matter content between 1% and by weight.

2. A method of producing an adsorbent cleaning material, comprising forming a mixture of from 1 to 30 parts by weight of sawdust and from 99 to 70 parts by weight of fullers earth, adjusting the water content of the mixture to a value between 40% and 60% by weight, extruding the mixture at elevated pressure above 100 pounds per square inch, drying the extruded mixture, reducing the dried mixture to granular particles, and calcining the particles at a temperature between 750 F. and 1200 F. for a 40 period of time sufl'icient to obtain a volatile matter content between 1% and 10% by weight.

3. A method of producing an adsorbent cleaning material, comprising adding 1 to 30 parts by weight of sawdust and 99 to 70 parts by weight of fullers earth, adjusting the water content of the mixture to a value between 40% and 60% by weight, thoroughly mixing the sawdust and fullers earth to obtain a homogeneous dispersion of sawdust in the earth, drying the resulting mixture, reducing the dried mixture to granular particles,and calcining the particles at a. temperature 5 between 750 F. and 1200 F. for a period of time sufficient to obtain a volatile matter content between 1% and 10% by weight.

4. An adsorbent cleaning material consisting essentially of granular fullers earth of 10 to 60 mesh and having a volume weight between 26 and 32 pounds per cubic foot, an oil retention between 0.8 and 0.9 pounds per pound of earth and between 24 and 27 pounds per cubic foot of earth, and a volatile matter content between 1% and 10% by weight, said cleaning material being produced by forming a mixture of from 1 to 30 parts by weight of a cellulosic material selected from the group consisting of sawdust, wood flour, and paper pulp, and from 99 to 70 parts by weight of fullers earth, adjusting the water content of the mixture to a value between 40% and 60% by weight, extruding the mixture at elevated pressure'above 100 lbs/sq. in., drying the extruded mixture, reducing the dried mixture to granular particles, and calcining the particles at a temperature between 750 F. and 1200 F. for a period of time suflicient to obtain a volatile matter content between 1% and 10% by weight,

WILLIAM S. W. McCARTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Chevalier Mar. 14, 1930 Simons et a1 Mar. 30, 1943 La Lande Nov. 28, 1944 FOREIGN PATENTS Country Date Great Britain 1930 OTHER REFERENCES Modern Soap and Detergent Industry, Martin (1931), vol. 1, section 3, page 23.

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